Research on the Importance of Feature Parameters in Seismic Sequence Type Determination Based on Decision Tree

Based on the catalog of 225 earthquakes with magnitudes 5 or above, the catalog of earthquake sequences, and the focal mechanism of the historical earthquakes in Sichuan-Yunnan region from 1966 to 2021, and referring to the previous research and practice on the estimation of the tendency of the aftershock activity, 10 sample datasets for the judging features of the earthquake sequence types have been constructed. According to the earthquake sequences types—swarm type, mainshock-aftershock type, as well isolated type—three labels have been made. After processing the imbalanced state and the missing state of the feature parameters, a decision tree model was used to study and analyze the importance of feature parameters. The results showed that there were differences in the importance categories of the feature parameters in different periods. As the sequence data increased, sequence type judgment relied more on dynamic sequence data; the parameters related to the main shocks’ focal mechanism and the main shocks’ parameters have a high contribution rate to the sequence classification, while the contribution rate of sequence parameters is extremely low. In overall, the results provided by the model are consistent with the actual empirical prediction methods. The above results can provide some ideas for the preliminary screening, exclusion, and selection of the complex and numerous feature parameters.